Prior art relating to the manufacture of laminated dynamoelectric structures includes:
(a) U.S. Pat. No. 4,110,895 to Mitsui which teaches apparatus for forming a stack of interlocking laminations which apparatus may be arranged to index laminations relative to each other; and
(b) U.S. Pat. No. 3,202,851 to Zimmerle et al relates to forming stacked interlocked laminations for dynamoelectric machines from sheet metal stock.
Each of the above patents disclose die apparatus having a plurality of stations for in seriatim operation for forming individual laminae.
U.S. Pat. No. 2,975,312 to Ploran relates to correspondingly formed projections and openings in adjacent laminae for interlocking a stack of laminae without a separate fastening element.
Other patents relating to this technology include U.S. Pat. No. 3,203,077 to Zimmerle, U.S. Pat. No. 3,189,984 to Haifley et al and U.S. Pat. No. 317,789 to Horton.